The present invention relates to a porous heat sink for actively cooling electronic components. In particular the present invention relates to a heat sink, which can be used in an LED lamp, especially a retrofit LED lamp, to cool the electronic components operating the LED lamp.
A retrofit LED lamp is a lamp using one or more white or monochromatic LED(s) as lighting means, and which is provided with electrical and mechanical connection means in order to use the retrofit LED lamp as replacement for incandescent bulbs, halogen lamps, . . . .
Heat transfer from heat sources, like the electronic components of a LED lamp, can be divided into the following processes. First, heat is conducted from the heat source to a heat sink or an air interface. Then, heat diffusion from the heat sink surface to convective regions of the air takes place, and the heat is transported away by convections in the air. The temperature drop is determined by material properties, e.g. the heat conductivity, heat flux density and conduction length of the heat sink. The lower the flux density of the heat sink will be, the lower also the temperature drop and the corresponding cooling effect on the heat sources will be. In practice, the larger the surface of the heat sink is, and the more turbulent the air affecting the surface of the heat sink is, the better the cooling effect of the heat sink will be.